On this night 150 years ago, slaves gathered in churches across the South for Watch Night, keeping vigil for news that the Emancipation Proclamation had gone into effect.

“It gave hope to many slaves who heard about it and who were waiting for Union troops, assisting them as teamsters, spies, washerwomen, cooks and soldiers,” said George Junne, a professor of Africana Studies at the University of Northern Colorado, who often teaches about the Emancipation Proclamation.

“There were also many slaves who believed the proclamation actually freed them, and who refused to work, ran away or stopped obeying orders,” Junne said.

In fact, the proclamation issued by President Abraham Lincoln on Jan. 1, 1863, freed only a small number of slaves by executive order and did not abolish slavery.

Today, scholars and activists are using the 150th anniversary of one of the most powerful symbolic actions in American history to re-examine its implications, to learn about what it did and did not do, and to consider the lessons it offers today.

“It’s something people talk about, but they don’t really know about it,” said Junne, who is working with members of the Colorado Black Round Table to have the Emancipation Proclamation read in their churches on Watch Night. “It’s helpful for people to educate themselves and their families about what it really says, and to realize that it didn’t free all that many slaves at all.”

Details of its history are endless, but the basics are simple.

The Emancipation Proclamation wasn’t law. As commander in chief of the Army and Navy, Lincoln claimed martial law allowed him to suspend civil law in states that were in rebellion.

It freed slaves only in the states that had seceded from the Union and didn’t cover the nearly half-million slaves in border states such as Maryland and Kentucky.

It gave Union troops a significant boost because it allowed black men to join in the fight for their freedom. By war’s end, nearly 200,000 black soldiers had enlisted. It also had significant international impact.

The Emancipation Proclamation expanded war goals to include abolishing slavery. Once that happened, England, which was preparing to support the Confederacy but had abolished slavery at home, could not support the South because slavery was morally unacceptable.

The South had “mills processing raw cotton into cloth, so there were economic reasons. But the Emancipation Proclamation stirred up a lot of anger among the anti-slavery people in England, which forced England to back off,” Junne said. “It was good public relations for the United States.”

Some of this history has been lost or blurred over the years.

In Five Points at Brother Jeff’s Cultural Center during Kwanzaa, discussions of the proclamation are woven into historical re-enactments that “connect the younger generation with their history,” said Jeff Fard, the center’s founder.

But conveying the notion that blacks once were property, who were freed by a constitutional amendment, is a challenge, especially since the election of President Barack Obama.

“Some say, ‘I can’t even relate to what you’re talking about becoming free — we are in the highest position of power,’ ” Fard said. “The work becomes teaching young people how we were able to make those transitions from where we were to where we are.”

In the 1950s, William King was a Cleveland high school student who had never heard of the Emancipation Proclamation.

Junne also is encouraging schools, libraries, community centers and churches to display a copy of the document this year — maybe compare it to copies of the preliminary proclamation, drafted Sept. 22, 1862, to see what changes were made. Ideas of compensation and colonization were dropped from the early draft, for example, while the use of blacks as soldiers was added.

“This is something that everyone has a historical stake in, whether their families were slaves, slave owners, for slavery or against it,” Junne said. “A lot of people think the Emancipation Proclamation is a black thing, but it’s not.”

The Denver Art Museum plans to funnel a $25 million one-time gift into the estimated $150 million budget for renovating its iconic North Building in time for the structure’s 50th anniversary in 2021, officials announced Thursday.